Alkynyl triazenes enable divergent syntheses of 2-pyrones

Abstract

The 2-pyrone motif occurs frequently in bioactive natural products and is appreciated as synthetic intermediates. However, only few methods allow for diversifying functional group modifications on this relevant heterocycle. The...

Gold-catalyzed synthesis of oxazoles from alkynyl triazenes and dioxazoles

“…According to the reported methods, we attempted to use acid to remove the triazenyl group to form the cation, which could be captured by various nucleophilic reagents. 8,9 Unfortunately, all these attempts were failed, probably due to the instability of 3-oxazole cation to trigger the ring opening. To our delight, heating 3a in CH 3 I at high temperature could obtain a 3-iodo oxazole in moderate yield, which provide an opportunity to further derivation via coupling reactions.…”

“…Originally prepared and demonstrated as ynamide analogs by Severin and co-workers, 6 the alkynyl triazenes have received considerable attentions in organic synthesis, especially in the construction of heterocycles and biologically valuable skeletons. 7 Typically, a variety of elegant works have been successively reported by Severin and Cramer, 8 and Cui. 9 The versatility of triazenyl group was subsequently realized by the diverse transformations of products in these reactions, thus representing modular, efficient and practical methods toward promising structures.…”

Facile Synthesis of γ-Butenolides and Maleic Anhydrides via Annulation of α-Keto Acids and Triazenyl Alkynes

“…Owing to their innate multiple functionalities, triazenyl alkynes have become increasingly popular in organic synthesis. Severin and co-workers have made great contributions to this research area, and the triazenyl group has been demonstrated to serve as a versatile removable moiety . Recently, our group has established a diastereoselective multicomponent reaction of triazenyl alkynes for the synthesis of trans -β-amino amides, and we also disclosed that triazenyl alkynes could undergo a triazene-directing cycloaddition with azides for the regioselective synthesis of triazoles .…”

Mechanistic insight into Cp*Rh(iii)-catalyzed Lossen rearrangement vs C–N reductive elimination for the synthesis of pyridones

“…Alkynyl triazenes displaying an ynamide-like reactivity are not sensitive to air or moisture, and possess high thermal stability. [12][13][14] Therefore, alkynyl triazenes have been utilized as the ideal candidate for fluoropyridone formation via transition metal-catalyzed C-H annulation.…”